Review by Klaus Schroiff, published March 2020

Introduction

The RF 15-35mm f/2.8 USM L IS is a big lens with similar dimensions and even a marginally increased weight compared to its EF "predecessor". Unsurprisingly, it follows the usual RF design philosophy. It uses some kind of very high compound material for the body, combined with big rubberized focus- and zoom rings. At the front, there's also the additional, customizable control ring for those who prefer to have an aperture, ISO or exposure control on the lens. Needless to say, the lens is also dust- and splash-proof. Fluorine coating on the front element helps to repel dust and water as well. However, a slight downside is the extending zoom mechanism. The inner lens tube extends by about a centimeter towards the WIDE end which is a little unusual. A very short, petal-shaped plastic lens hood is part of the package.

The AF is, once again, based on Canon's Nano USM which offers both very fast as well as noiseless AF operations. Focus accuracy is very high at 15mm but it suffers a little beyond when stopped down a bit (residual spherical aberrations). To be fair - in real life, any inaccuracy will usually be hidden within the immense depth-of-field. Manual focusing works "by wire" but other than the lack of a focus distance scale, you won't really notice much of a difference compared to a mechanically coupled focusing system. The IS has a claimed efficiency of up to 5 f-stops. Based on our real-life experience with the lens, we'd say that it's 1-2 f-stops less than that though.